1. Field of the invention
This device and process relate to the field of fluids separation and more particularly to separation of electronegative molecules from non electronegative molecules using electric fields. One of the most useful electronegative molecules is oxygen, O2. In the atmosphere, it is mixed with primarily non electronegative molecules.
2. Background information
Many important environmental, chemical, medical, and electronics technologies require pure oxygen. For example, it is used in clean coal combustion technologies to produce gasification of coal. It is also used in CO2 reduction as oxygen fuel combustion to produce a concentrated stream of CO2 for sequestration.
The high cost of high purity oxygen has negatively impacted many applications because it is largely produced by cryogenic air separation, where air is cooled down to the condensation point of nitrogen (−210 C). The components are then separated in large columns. This process requires expensive, maintenance intensive equipment, with high energy consumption.
Another method of gas separation is the use of selective membranes which pass only desired components. Mixed Ionic Electronic Conducting Membranes rely on transport of oxide ions (O——) through the membrane to separate oxygen from air. The process has low throughput and requires high temperatures for the ion conduction to take place. The reaction is driven by a high pressure differential across the membrane or the reaction can be driven by an external electric circuit known as active oxygen pumping. Hydroxide conductive membranes rely on the transport of hydroxide ions (OH—) through the membrane and require a high pressure differential or an external electric circuit.
A fuel cell can also be used to separate gases such as oxygen or hydrogen by supplying a mixture of gases to one electrode with a potential difference to a counter electrode separated by a polymeric ion exchange electrolyte. The hydrogen or oxygen may be generated by the decomposition of water or may be transported through the electrolyte in ionic form, depending upon whether a polymeric cation or anion exchange electrolyte is employed.
All these methods require high energy input through compression or electric power, which requires at least one electron, from an external circuit, for each molecule separated.
Therefore, there exists a need to produce high purity oxygen in a more efficient manner with less complex and more compact equipment.